diff --git a/src/tbf.cpp b/src/tbf.cpp
index a3793638..c8659cfc 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -46,6 +46,11 @@ gprs_rlcmac_bts *gprs_rlcmac_tbf::bts_data() const
 	return bts->bts_data();
 }
 
+uint32_t gprs_rlcmac_tbf::tlli() const
+{
+	return m_ms ? m_ms->tlli() : m_tlli;
+}
+
 void gprs_rlcmac_tbf::assign_imsi(const char *imsi)
 {
 	strncpy(m_imsi, imsi, sizeof(m_imsi));
diff --git a/src/tbf.h b/src/tbf.h
index a2f5bf72..a1edff37 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -293,11 +293,6 @@ inline GprsMs *gprs_rlcmac_tbf::ms()
 	return m_ms;
 }
 
-inline uint32_t gprs_rlcmac_tbf::tlli() const
-{
-	return m_tlli;
-}
-
 inline bool gprs_rlcmac_tbf::is_tlli_valid() const
 {
 	return m_tlli_valid;